Commit e66fe357 authored by Minjong Chung's avatar Minjong Chung Committed by Anssi Kääriäinen
Browse files

Fixed #21102 -- pickling a QuerySet with prefetches twice 

Fixed the bug that a QuerySet that prefetches related objects cannot be
pickled and unpickled more than once (The second pickling attempt
raises an exception).

Added a new test for the queryset pickling idempotency.

The bug was introduced by
bac187c0.
parent dbc2e8eb

django/db/models/query.py

+2 −2
Original line number Diff line number Diff line
@@ -80,10 +80,10 @@ class QuerySet(object): 
        if model is None:

            # if model is None, then self should be emptyqs and the related

            # objects do not matter.

            self._known_related_objects = {}

            obj_dict['_known_related_objects'] = {}

        else:

            opts = model._meta

            self._known_related_objects = dict(

            obj_dict['_known_related_objects'] = dict(

                (opts.get_field(field.name if hasattr(field, 'name') else field), val)

                for field, val in obj_dict['_known_related_objects'].items()

            )

tests/regressiontests/queryset_pickle/tests.py

+12 −0
Original line number Diff line number Diff line
@@ -73,3 +73,15 @@ class PickleabilityTestCase(TestCase): 
        empty = pickle.loads(dumped)

        self.assertQuerysetEqual(

            empty, [])



    def test_pickle_prefetch_related_idempotence(self):

        p = Post.objects.create()

        posts = Post.objects.prefetch_related('materials')



        # First pickling

        posts = pickle.loads(pickle.dumps(posts))

        self.assertQuerysetEqual(posts, [p], lambda x: x)



        # Second pickling

        posts = pickle.loads(pickle.dumps(posts))

        self.assertQuerysetEqual(posts, [p], lambda x: x)